Optical fiber hydrogen sensor based on self-assembled PDMS/Pd-WO3 microbottle resonator.

In this paper, a new optical fiber hydrogen(H 2) sensor based on a self-assembled microbottle resonator was proposed. The self-assembled microbottle was simply obtained by coating the single-mode fiber (SMF) with an internal composite material layer of palladium-tungsten trioxide (Pd-WO 3) that was sensitive to H 2 and an outer organic polymer material layer of polydimethylsiloxane (PDMS) with a significant thermal response. The microbottle resonator was further fabricated by coupling a tapered fiber with the self-assembled microbottle to excite whispering gallery mode (WGM). When the WGM resonator is exposed to H 2 , H 2 molecules penetrate the PDMS and undergo redox reaction with the Pd-WO 3. After the PDMS absorbs the reaction heat, its volume and refractive index will change, along with the wavelength shift of the WGM resonator. Therefore, a simple and low-cost H 2 sensor is realized by observing the shift of resonance wavelength. Experimental results showed that the hydrogen sensor had a maximum sensitivity of − 3.091 nm/% at 25 ℃. And the resonance wavelength just shifted a small distance when the relative humidity increased from 22.87 % to 84.59 % or the temperature rose from 20.2 ℃ to 30 ℃, which indicated the sensor had preferable resistance to disturbances of external humidity and temperature. • A simple and low-cost optical fiber H2 sensor was proposed with high sensitivity of − 3.091 nm/%. • The self-assembled microbottle was simply fabricated by coating Pd-WO 3 and PDMS on a fiber in sequence. • The sensor has preferable resistance to disturbances of external humidity and temperature. [ABSTRACT FROM AUTHOR]